1. Field of the Invention
The present invention is generally related to a fluorescent gold nanocluster, and more particularly to a tunable fluorescent gold nanocluster.
2. Description of the Prior Art
Recently, quantum dots with excellent optical characteristic have successfully overcome the threshold in biological and medical optical probes to become important nano-materials as new generation fluorescent probes. There are great advances and breakthroughs in cellular 3D imaging, long-term living cell monitoring, single-molecule dynamic intracellular tracing, long-term optical sensor fabricating and research, diagnosis and therapy for cancer. Besides, since quantum dots are quickly industrialized and have great business opportunity, they become a very successful role model in nano-biotechnology. Particularly, gold metal fluorescent materials are preferred that have high electron density, high contrast under an electron microscope, and very high biocompatibility and are proven to be successfully applied in various biomedical labeling or optical component fabrication by altering the size of clusters to have different color of fluorescence. However, the fluorescence characteristic of such materials is far inferior to commercially available Cd-based or Pb-based (toxic heavy metal based) water-soluble quantum dots. In addition, due to difficulty in fabrication and mass production as well as time consuming in fabrication, up to now the development in biomedical application is limited. Therefore, it is an important task to develop a fluorescent gold nano-material having the characteristics of being easy to be fabricated, low-cost, having low environmental toxicity and tunable fluorescence.